ASP.NET Identity 2 Remember Me - User Is Being Logged Out

There is an explanation for TimeSpan parameter in similar question. Simply use the infinite cookies, like this:

OnValidateIdentity = SecurityStampValidator
  .OnValidateIdentity<ApplicationUserManager, ApplicationUser>(
  validateInterval: TimeSpan.FromMinutes(0),
  regenerateIdentity: (manager, user)
  => user.GenerateUserIdentityAsync(manager))

This is also needed for it to work correctly:

Call

await UserManager.UpdateSecurityStampAsync(userId);

before

AuthenticationManager.SignOut(); 

I think you should read this article . There are two different intervals: ValidateInterval and ExpireTimeSpan. And in your case i think you should change the expireTimeSpan, not the ValidateInterval.